1. Field of the Invention
The present invention relates to a magnetic recording/reproducing device and, in particular, to a magnetic recording/reproducing device which is provided with a track search function.
2. Description of the Related Art
In a magnetic recording/reproducing device for use in an electronic still camera or the like, a video signal which represents an image is to be recorded in a magnetic recording medium such as a magnetic disc having a small aperture and the like. In the magnetic disc, a number of, for example, 50 tracks are formed concentrically at substantially regular intervals. In the respective tracks, one field of video signals corresponding to one frame is recorded in the sequential order beginning with the start track of the unrecorded tracks thereof. In the light of this, in order to be able to record the video signal at once responsive to a recording instruction, it is preferable to have previously arranged a magnetic head on the start track of the unrecorded tracks. In particular, in an apparatus such as an electronic still camera with which shutter timing is important, it is necessary to execute a track search at a high speed prior to photographing in order to check whether all of the tracks accessed, have been previously recorded on or not.
In view of this, in the above-mentioned type of electronic still camera, the magnetic head is moved at a track pitch over all tracks, a signal is read out only once from one position in each of the tracks sequentially accessed by the magnetic head, and, in accordance with the signal, it is determined whether or not the accessed track has been recorded on.
However, due to the fact that in the above-mentioned track search the magnetic head is moved at the track pitch and the signal is read out only once, if the magnetic disc is expanded or contracted by the effect of temperatures or the like, the magnetic head may be moved to a position which is out of the actual track, with the result that the signal cannot be read out accurately. In other words, there is a problem in the above-mentioned conventional device that the determination of whether or not the accessed track is recorded on is in error.
Also, when any possible deformation in the magnetic disc results in poor contact between the magnetic head and the magnetic disc, or when the magnetic head has a varying frequency characteristic, the level of the reproducing output of the device is caused to vary. As a result of this, similarly as in the above-mentioned case, the determination of whether or not the accessed track is recorded on may be in error.